The formule is about area of a circle.

We need to solve the equation for x. Where x is the radius of the circle.
In order to solve it for x, we need isolate it for x on left side.
So, first we need to get rid pi from left side.
On dividing both sides by pi, we get


Taking square root on both sides, we get


Answer:
equation- 4÷x=-7
x= -4/7
Step-by-step explanation:
Diameter of the semicircle = 10 km.
Explanation: perimeter of semicircle = 1 2
the circumference + diameter Given: perimeter of semicircle = 25.7 k
m
Circumference of circle with radius r
= 2
π
r where 2
r
= diameter ⇒
25.7
=
22
π
r
+
2
r
⇒
25.7
=
π
r
+
2
r
=
r
(
π
+
2
) ⇒
25.7
=
r
(
3.14
+
2
)
=
r
(
5.14
) ⇒
r
=
=5m
⇒d
i
a
m
e
t
e
r
=
2
r
=
10
k
m
Answer:
1358024679
Step-by-step explanation:
Formula= 4/3(3.14)r^3
4/3(3.14)(70)^3
4/3(3.14)(343,000)
4/3(1,077,566.28)
=1,436,755.04